A Tale of Two Conservatives

One test for economic conservatives is whether they are willing to oppose constituent business interests looking for government favoritism. On that score, two recent contrasting votes by Jim DeMint of South Carolina and Marco Rubio of Florida are instructive.

Last month the Senate easily voted to reauthorize the Export-Import Bank, 78-20, a vote that was never much in doubt given the backing from business lobbies and the White House. But it's still worth saluting the 20 votes in opposition—19 Republicans and independent...